Authors

Discussion

Aims: Grazing animal species kept in zoological collections can be at risk of significant gastrointestinal nematodes (GIN) infections, due to life-cycle maintenance in confined grazing areas and proximity to other susceptible hosts. Yet little work has been undertaken to understand the GIN species dynamic within co-grazed host-species. This pilot study aimed to describe the species diversity of nematode species found in faeces of grazing animals in a Scottish zoological collection.

Methods: At a single time-point, fresh faecal samples were collected randomly from the ground of the studied animals’ enclosures including horses, sheep, alpacas, deer and tapirs. Faecal worm egg counts (FWECs) were conducted using a saturated saline centrifugal flotation cuvette technique. The nematode species profile was estimated through deep-amplicon sequencing of ITS-2 and mitochondrial markers to understand infection dynamics between host-species.

Results: There was a 95% prevalence of gastrointestinal nematode infection. Magnitude in faecal worm egg counts varied between individual host-species (p<0.01). Apart from goats with a FWEC 460epg, all other animal groups had egg counts <200epg. There were various gastrointestinal parasite species found across host-species, including the potentially pathogenic species Haemonchus contortus and Teladorsagia circumcinta. Potential transmission dynamics, between host species, were explored by phylogenetic trees. Mitochondrial markers were also compared using other animal holdings in the UK to explore the population structuring.

Conclusion: The variation in egg counts and parasite species suggest how different host-species and management factors could influence transmission. A high prevalence of GINs was found across all host-species. In particular, the increased egg count found in goats and the presence of potential pathogenic species (H. contortus) indicates the importance of regularly monitoring levels of parasitic infections in mixed-host-species zoological collections to develop sustainable control programmes.